If the temperature is extraordinarily hot, Does car AC loose some of it's efficiency? When it's Triple Digits it takes forever for my car to cool down. when it's 90's it's fine. cools down pretty quickly. the system is new, new compressor, evap, dryer most of the hoses are new too, the ones that are not new were flushed out and the entire system charged with something, I assume nitrogen or something similar to check for leaks. my system holds the same pressure my indy put in (had them check it).. something I should be concerned with? the car when it gets cool, stays cool and the air coming from the vents is always cold.

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Certainly its less efficient. My understanding is that AC systems, in general, drop the incoming air XX number of degrees. For example, a small AC window unit for a house will take the incoming air (usually from inside the home) and cool it by lets say 15 degrees. So if the air coming in is 90, it will output 75 degrees. And if the air coming in is 70, it will output 55 degrees. Different systems have different levels of efficiency, usually measured in BTUs.

Make sense? Therefore if its REALLY hot out, it will only get so cold. Not to mention the car itself is not the best insulated. One thing that helps is to turn off any fresh air vents, like the 126 has in the back, and to set it to only cycle inside air. That lets the system then cool already cooled air and work more efficiently.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

Plus running 134A in a system meant for R12 doesn't help.

I'd like to do a parallel flow condenser in my car

I am disappointed that I did not get the R-12 I wanted. but there's one shop in town that still does it and well... they are idiots. and it's not worth buggering around with the system to change it up. so 134a will stay today.... what is a parallel flow condenser? is it as it sounds?

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Ya. I think when a system is converted there is even a curve to it. In other words, at 90 it may only be able to drop it 10 degrees, at 80 incoming maybe 12 degrees and at 70, 15 degree drop. These are just random numbers for explanation.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

If you think of heat as a commodity and the job of AC to remove heat from the cabin and discharge it outside the car, you can picture how it's increasingly difficult to discharge heat to surroundings that already contain a lot of heat. It's like packing a suitcase that's already full.

Sixto
87 300D

yeah... I can see that. I just wanted to double check and make sure I dont have an issue going on.

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

all true above.
however, if the condenser coil is building up a layer of bugs on it, you will loose capacity. and the 134 has already lost about 30% of the system's capability.
also, the heat from the sun, and the heat buildup inside the car before you start it is just incredible.
park under a tent, install high e tint, and keep the RPM of the vehicle above 1500 to maximize the flow of refrigerant.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!